1. Field of the Invention
The present invention relates to viewing devices, and more particularly to reflective probes adapted for insertion into cylindrical bores.
2. Description of the Prior Art
In many applications inspection of the lateral walls of circular openings is desired, often entailing the examination of microscopic bores formed in electronic circuit boards. Such inspection is quite often best performed optically either through microscopic enlargement or through the measurement of the reflectivity of the wall. In each instance the course of such inspection entailed the insertion of probes which in themselves created a larger risk of damage to the bore walls than the damage or flaws detected.
Thus, examination of delicate electronic instruments and particularly examination of through plated holes in printed circuit boards has been heretofore relegated to post assembly tests or has been achieved with very elaborate and expensive viewing devices not practical in commercial use. The physical constraints, furthermore, entailed in examining a small opening are equally applicable to the examination process of high precision bores like the cylinder bores of an internal combustion engine. In each instance accurate axial alignment with the bore center is necessary and full rotational freedom is required in order to inspect all of the bore surface. Both in the microscopic opening and in the larger bores accurate advancement of the viewing instrument is necessary in order to both locate the flaw and determine the magnitude thereof. It is towards these ends that the present invention is erected. The features thereof being usable regardless of scale and regardless of the function or end use to which the inspected bore is put.